This invention relates generally to wood panels of reduced cost, utilizing waste products which have improved dimensional stability and, more particularly, to composite laminated panels having wood veneer surfaces which may be ripped or sawed along the grain to produce structural lumber. These structural panels and laminated veneer lumber (LVL) have utilities as components of furniture, replacement for lumber in building construction, and are suitable for use as substitutes for conventional lumber or plywood.
It has been previously proposed to manufacture plywood having a plurality of adhesively-bonded wood veneer lamina for use in the construction of buildings. It has also been proposed to make composite wood panels having surface wood veneer sheets, and a core of lignocellulose or the like particles adhesively bonded together to form a mat, which is disposed as a core between the veneer sheets and adhesively bonded thereto. One of the problems inherent in prior art panels is that lateral expansion of the panel across the grain as the panel absorbs moisture, which causes warping and buckling of the panel. The dimensions of the lumber ripped from these panels do not satisfy the requirements of lumber, and the expansion, warping and buckling of the panel also exists in the structural lumber ripped from said panel, and further detracts from its usefulness as a substitute for structural lumber.
It has also been proposed to make laminated veneer lumber directly by gluing wood veneers together with the grain of all plies running parallel to each other. This material is produced in panels and ripped along the grain to produce structural lumber.
Another proposal forms wood strands, blended with resins, into a mat, with the strands oriented in a parallel direction. The mat, pressed to produce an oriented strandboard or flakeboard, is transferred to a lay-up station. Depending on the end use, the strandboard is ripped to the desired width and then laminated with veneers on the edges to produce a stud, joist or other structural product. However, none of these prior art products provided dimensional stability coupled with the strength required as a substitute for structural lumber.
There is therefore a continuing need for the production of structural panels and lumber which may be manufactured at relatively low cost, and avoids disadvantages of dimensional instability of the prior art laminated panels. Additionally, there is a need for laminated veneer lumber which may be substituted for conventional structural lumber, including the acceptance of fasteners, such as nails, staples, screws and the like, without splitting or delaminating upon installation of the fasteners or when subjected to stress, such as occurs in the normal use of structural lumber.